My thanks to Philip Hill for bringing this concise article to my attention.
This article addresses the potential involvement of deficiencies in B12 Vitamins in chronic fatigue, ME, SM, Parkinsons, Depression, Multiple Chemical Sensitivity, Lyme disease and more.
B-12 Deficiency in ME/CFS and FM May Provide Clues & Relief (Footnoted Version)
I would like to bring your attention to the lecture here, which may throw light on the potential involvement of gluten in this scenario. This is a very important observation.